Guidelines for using 12v refrigerators on EV/Tesla road trips

Recently, a large number of 12-volt mobile refrigerators for automobiles have appeared on the market.You would think that they are a perfect match for electric cars equipped with huge batteries, but Tesla’s TSLA’s mistakes made this much more difficult than it should be.

 

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These are compressor-based refrigerators, just like refrigerators at home, which can maintain low temperatures with high efficiency, including freezing.This is different from old Peltier-based refrigerators, which are inexpensive, inefficient, and can only reduce the temperature by about 40 degrees Fahrenheit.(In other words, in hot weather, they cannot keep the food at a safe temperature and need to add ice.)

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For a long time, people put ice-based coolers in their cars on road trips.They are suitable for cold drinks and perishable snacks, and can be used to preserve leftovers or purchase items such as cheese and meat.However, they are working hard to maintain and need to constantly replace the ice cubes.The water condenses into a pool at the bottom, and you will make mistakes from time to time and lose some perishable food.It is usually necessary to bring all the food or the entire cooler to the hotel room to use the refrigerator there, unless there are enough ice cubes for you to spend the night.
These compressor refrigerators only consume about 40 watts of power, and the running time is about 1/3.They plug into the 12v accessory port (often called the cigarette lighter port) of any car.With this electrical load, they will use about 400 watt-hours of energy to run the entire day.This is fine when you are driving, but if you leave for half a day, it is enough to severely deplete a typical gasoline car battery.Therefore, if their battery is too low, they can all be set to off-this is a decision to keep the refrigerator warmer than not being able to start the car.

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However, in electric vehicles, 400 watt-hours is nothing.A range of less than 2 miles can be used for a day’s cooling.Now, you can choose a refrigerator that maintains a moderately low temperature throughout the trip, without maintenance or adding ice.The cost comes from money (purchase price of US$250 to US$500) and weight, as well as the space occupied by the compressor, although this space is comparable to the space occupied by ice.There is also a small amount of noise during operation.Refrigerators have other uses at home, such as:
This is the second in the EV road trip series.Please refer to Part 1, about using CHAdeMO charging adapters in Tesla.Part 3 will introduce general remote area charges.
As mentioned earlier, using only 2 miles a day sounds great.The problem is that Tesla’s system is designed to open the accessory port, and the car computer system must be fully opened, which consumes about 300 watts of power.300 watts allows you to turn on the refrigerator with an average of 15 watts.Tesla aims to go to sleep as much as possible and shut down most systems, including the 12v port.In this mode, you cannot leave the refrigerator in the car for a long time.It is of course also a well-insulated cooler, so it can handle an hour or two, but not more.
There are many ways to order Tesla not to sleep.The easiest way is to turn on its “Sentinel Mode” security system, which monitors suspicious activity near the car and records its video.The problem is that this attracts all these forces.Leave it overnight and you will lose about 15 miles of range.The same is true for other methods such as “camp mode” and call standby mode.If you are plugged in or you are on your way to the charger in the morning, this is not a problem, but sometimes you are saving range, which is not a good idea.So you need other solutions.
The simplest solution is to put or keep some ice cubes in the refrigerator.You don’t need to put in as much as in the cooler, and you only need it if you have a longer sleep time.The problem is that you have just eliminated one of the core advantages of the refrigerator-no fuss.Ice cubes are troublesome.You can buy too many ice packs in the store.In most American hotels and motels, you can fill an ice pack, but you need a very sturdy ice pack, otherwise it will leak and they will have condensation on it.You can also freeze water bottles and ice packs and put them in plastic bags to collect condensate.The problem is that most hotel mini refrigerators cannot freeze ice packs.
Another solution is to use a backup battery of approximately 200 watt hours, which is sufficient for one night and other long stays.The battery is charged when the power is on, and the refrigerator is powered when the power is off.This can also work, but it’s very stupid in a car, where you have a huge battery just sitting there.Portable battery packs are popular, but they cost about $200-a large part of the cost of refrigerators.Lead-acid batteries can do this at a much lower price, but such products are not easy to obtain-refrigerator manufacturers are best to connect standard batteries to their refrigerators, whether it is a gasoline car or an electric car.
A surprising choice also applies to the refrigerator I bought, Alpicool T-36.This unit can have two rooms with two temperatures, usually a refrigerator and a freezer.I don’t use a refrigerator too much on the road, so I set one room to store perishables at 36 degrees and the other to store drinks at 45 degrees.I found that by placing a rectangular juice bottle on the back wall of the colder part, right where the cooling coil is, it can keep the frozen bottle frozen!I only need to replace the ice cubes when I have to go to the storage range for 2 nights.Better, but still not perfect.You don’t need to add ice in the 45 degree room, because the beverage can handle getting hot.
For refrigerator manufacturers, another good solution is to provide a place specifically placed on the cooling coil.If the owner fills it with water, it will freeze the water and use it for cooling when closed.Facts have proved that ice is a good way of energy storage, much cheaper than batteries, if all you want is cooling energy.Every day, while driving, the ice will re-freeze, ready to cool down at night and during rest during the day.
Customers have always been curious.Tesla has a power supply DC to DC converter that converts the 350 volts of the main battery into 12 volts to run computers and accessories.When the car goes to sleep, this function is turned off, so the car is also equipped with the same standard 12v battery as any gasoline car.When the car is asleep, the battery provides power.If needed, it will turn on this computer from time to time to prevent low battery power.It is speculated that the additional continuous consumption of such batteries will cause them to degrade faster-these batteries are notorious for malfunctioning-but this is unproven.Some owners have placed manual taps on 12v power supplies to plug in smaller things, but this requires hardware modifications.Maybe Tesla does have a method in the future firmware that allows you to turn on DC->DC without turning on other computers to reduce power consumption.
It is also possible to turn on the converter in 1/3 of the time (or even the entire 300w unit), and only sleep in 2/3 of the time.This will provide the refrigerator with more drainage capacity you want, but it will have much less drainage compared to running it at full capacity all the time.Tesla can even be very clever to observe the power consumption of the refrigerator, turn on the power until it stops running, and then sleep for a while.
Some electric vehicles have or will have 120v sockets, powered by internal batteries through a dedicated inverter.Tesla did not put such sockets in their cars.Although the efficiency is low, these refrigerators are usually equipped with a converter that can convert it back to 12vdc, as long as the inverter is always on.Some vehicles, such as the high-end Ford F-150, promise to have large enough inverters to power large electric tools and even homes.To be used in refrigerators, they must be able to work with low, constant loads at low power.
There are various 12v compressor refrigerators on the market, most of which are imported from China.They are heavier and larger than many coolers and require space for the compressor, although coolers usually take up more space than the space filled with ice cubes.There are also domestic brands with higher prices.Due to the customer’s favorable comments, Qixuan was purchased.This special model T-36 is unusual in price because it can be divided into two compartments at two temperatures, one of which is a freezer.However, as a freezer, it takes nearly 2 days to freeze a gallon of ice, but it does work.It is not clear how many freezers you need on a road trip, but it is valuable in an RV.
In almost all cases, you can get the same unit of different sizes by getting a higher version.This version is very long (occupying 1.5 passenger seats in the back seat) but short enough to fit in the trunk.It also has other secondary functions, such as a USB port and Bluetooth interface.At first I thought Bluetooth was a gimmick, but it does make configuration easier, and it also allows you to confirm from a distance that it is turned on and what temperature it is at.When experimenting with overnight power, it turned out to be useful.(There are no security measures, so a malicious person can remotely shut down your refrigerator and spoil your food.)
The biggest flaw of this unit is the lid.It just closed suddenly because of friction.Because it is shipped too tightly, you need two arms to open the lid!You can archive tabs, but this has its own risks and is still difficult to open.Even better are the magnetic seals or latches used on almost all household refrigerators.This lid is a bad choice, and it alone is sufficient to consider other units.This one has wheels-full of food, it can be heavy, as long as you don’t climb the stairs, you can easily move it to the hotel room.We didn’t do it in the end-our goal was to leave it in the car and use battery power, and then bring some food to the room as needed.If you do this, it will be equipped with an AC power supply unit, and if you park your car near the plug, it will provide another option to supply electricity overnight.(If you park your Tesla near the plug, you can also charge the car and keep the refrigerator and computer on, but not all plugs can cope with this challenge. This will take up the 50 miles you get this way 15 miles in the refrigerator.)
If you are wondering about the cardboard box, it is there, because with any top-loaded cooler or refrigerator, when you take out the bottles, small items will fall into the space they occupy and you have to make a fuss to put things back in. Where. This unit comes with two less useful wire baskets-but a way of organizing parts for different projects can be very convenient.
The refrigerator allows you to have a relaxing picnic at any charging station, especially in rural rest areas…. [+] More chargers should have picnic tables, but you can also carry equipment in the car.
For cold drinks only, this may be too much work.After all, if you run out of ice, drinks can survive, and perishable food will spoil.This can be great, and can save a considerable amount of money to carry food to make breakfast and dinner in a motel room with a kitchen or in a microwave.As an alternative, there are foods that are not perishable.In the United States, many people do not know this, but only in the United States and Canada, they require eggs to be washed before they are sold in stores, which requires them to be refrigerated.In other parts of the world, eggs are sold unwashed and kept at room temperature.You can often find such eggs from farm stalls.
Nevertheless, it is good to be able to take away the leftovers and have other food on hand even when eating in a restaurant, and many people think it is worth it.These refrigerators are also becoming more and more popular in small RVs.Traditional RV refrigerators work by boiling refrigerant and condensing it.They are usually boiled with propane, but they can also be boiled with electricity.They can even boil it with 12 volts, but the efficiency is very low, and running the RV refrigerator at 12 volts will quickly drain the battery.These new compressor refrigerators cannot use propane, but can run on electrical systems with decent batteries, especially if these systems are supplemented by solar power or occasional generators.The main advantage of propane is that a typical RV can run on a large propane tank for several weeks of heating and refrigerator operations, with almost no risk of running out of batteries and damaging food.
Over time, refrigerators that can run on electric vehicle batteries for months will incentivize some electric vehicles to incorporate refrigerators into their vehicles, especially those aimed at the road trip and leisure/off-road markets.These will be designed to be used in conjunction with EV power systems, and may draw power directly from high-voltage batteries.
These refrigerators are only suitable for local travel.They may not be transported on airplanes due to internal fluids, but it makes sense for car rental companies or other companies to rent them out to people who are flying/driving road trips.Then the extra battery can even become part of the package.


Post time: Jan-03-2022